Efforts to Contain the Armyworm Invasion in Ghana
By Article by Gabriel Adukpo
IN the late 1990s, this writer ever watched a long line of caterpillars matching and devouring crops in a young maize farm. They lined up as if they were students who had returned from holidays and weeding their football field in a stretch side by side. These creatures appeared to have an efficient digestive system as they ate and left their droppings continuously on their way across the field.
Hand picking was almost impossible due to the large numbers. However, the soft-bodied larvae were susceptible to insecticide application. Worm-eating birds hovered around to pick the dead caterpillars raising concerns about chemical contamination of the food web.
The pest in question had been identified as African armyworm, Spodoptera exempta. Indeed they were like soldiers in the infantry brigade. Somehow, such occurrences have been uncommon in Ghana. Apart from weevils in stored cereals, farmers seldom make provision for pesticide use except in certain cases where stem borers attack maize, rice, millet and sorghum.
Fall armyworm in Africa
Africa woke up one morning in 2016 to see the fall armyworm, Spodoptera frugiperda at the doorsteps of some countries. The pest did not hesitate to launch attacks on crops in at least 14 countries including Ghana. It was reported that fall armyworms destroyed 4,500 hectares of crops in Ghana that year. Kenya, Malawi, Zambia and Zimbabwe were among the hardest hit countries in Africa.
Spodoptera frugiperda is native to tropical and subtropical regions of North and South America. It is a moth and as such has a life cycle that goes through egg, larva, pupa and adult stages. It is a polyphagous pest and large populations of the larva can cause defoliation resulting in yield losses in affected crops. The fall armyworm is believed to have been introduced into the continent of Africa by accident.
The presence of fall armyworms in Ghana was first reported in Yilo Krobo municipality. Its infestation was initially mistaken to be stemborer attack. A report was made to the plant clinic being run by the Department of Agriculture with the support of Centre of Agriculture and Biosciences International (CABI).
Having been diagnosed as fall armyworm, it became clear that the pest was present in nine regions of the country.
It would not be difficult to detect the fall armyworm on the field given the publicity the new pest has attracted. Since the beginning of the major season in 2017, reports in all ten regions speak of gregarious, leaf-eating caterpillars damaging large hectares of maize fields. Worse still, they enter the whorls and cover up with fras thus complicating their control. The economic impact of this insect pest looks frightening.
The Government reacted swiftly; and it has cause to. The government’s GHC 560m programme dubbed Planting for Food and Jobs was under threat. An additional fund of GHC 16m was released to fight the menace. Insecticides were purchased and distributed to all the regions. A national taskforce was established to oversee the implementation of control measures.
Refreshingly, the Ministry of Food and Agriculture and its Plant Protection and Regulatory Services Directorate, the Research Community (CSIR), International agencies (FAO, USAID, DFID, CABI, AGRA), extension officers and farmers have been all in arms against the fall armyworm. In an explosive situation such as this unexpected invasion, chemical application was the first line of action. The notoriety of the pest and logistics constraints notwithstanding, the fight has been unrelenting on the field. This assurance was received through telephone chats with some District Directors of Agriculture in Ashanti, Brong Ahafo, Central, Eastern, Northern and Volta Regions.
As we await the full statistics of the havoc caused by the fall armyworm, we should be planning for other control measures. Biological and cultural methods are alternatives worth exploring. Each should not be adopted in isolation but rather be combined in integrated pest management programmes. It is also necessary to collaborate with countries in the sub-region and the continent as a whole because of the migratory nature of the pest.
All hands must be on deck to fight the pest. When we persist and apply all the necessary measures, we would be in a position to declare the fall armyworm, insecta non grata in Ghana.